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C-Dory floatation
- Thread starter DAVEY5205
- Start date
DAVEY5205":3vswd3x1 said:is it possible to actually sink my c-dory or do they just float when swamped? :?
dave
Years ago, I saw a picture at the factory of a 16' C-Dory that was intentionally filled with water and it was floating. (As a side note, I'm not certain if a 22' will "pass" the same test.....does anyone know?...it seems to me we've discussed the 22' before).
The only real flotation in a CD-22 is in the sealed area under the v-berth.
Fiberglass doesn't float, neither does the engine, and batteries are mostly lead and very dense electrolyte which is much heavier than water.
If you have wood cabinets, it's a little help, but not all that much in volume. The air in the water tank will help some to the extent that the water is drained. Gas is about 7/10 as dense as water, and any air in the tanks helps reduce the density more, but won't support 500 lbs of motor(s) and at least another 100 lbs of batteries, etc. The balsa core in the hull will lessen the load of the fiberglass, but overall there's not much flotation here outside the forward flotation tank.
There's a lot of stuff in the boat that will float free, but a lot of heavier stuff that's bolted down and wants to find it's resting place in Davey Jones Locker.
Seems to me the best to expect is that the front end flotation will keep the nose of the boat afloat, albeit upside down and pretty much awash. The engine's weight will be hanging at the bottom of the floating mass with the air chamber at the top.
It would probably float just enough to allow it to be towed away from the rocks/surf to deeper water if needed and only if help arrives in time. Sometimes it's probably better if the boat sinks somewhere safe from further damage until it can be later raised and rescued.
The project boat that was rebuilt had most all of the cabin top sheared off, lending support to the idea that a swamped boat turtles and floats upside down.
My 30 years racing dinghy sailboats would lead me to believe that the bow flotation is very marginal and that the barely afloat/awash inverted scenario is the best guess. Better would be to test it out, but no one's going to volunteer their boat, so the best approach is to see if it's already happened by accident. Are there any detailed accounts of the recent sinking in Alaska that would answer the question? Joe.
Fiberglass doesn't float, neither does the engine, and batteries are mostly lead and very dense electrolyte which is much heavier than water.
If you have wood cabinets, it's a little help, but not all that much in volume. The air in the water tank will help some to the extent that the water is drained. Gas is about 7/10 as dense as water, and any air in the tanks helps reduce the density more, but won't support 500 lbs of motor(s) and at least another 100 lbs of batteries, etc. The balsa core in the hull will lessen the load of the fiberglass, but overall there's not much flotation here outside the forward flotation tank.
There's a lot of stuff in the boat that will float free, but a lot of heavier stuff that's bolted down and wants to find it's resting place in Davey Jones Locker.
Seems to me the best to expect is that the front end flotation will keep the nose of the boat afloat, albeit upside down and pretty much awash. The engine's weight will be hanging at the bottom of the floating mass with the air chamber at the top.
It would probably float just enough to allow it to be towed away from the rocks/surf to deeper water if needed and only if help arrives in time. Sometimes it's probably better if the boat sinks somewhere safe from further damage until it can be later raised and rescued.
The project boat that was rebuilt had most all of the cabin top sheared off, lending support to the idea that a swamped boat turtles and floats upside down.
My 30 years racing dinghy sailboats would lead me to believe that the bow flotation is very marginal and that the barely afloat/awash inverted scenario is the best guess. Better would be to test it out, but no one's going to volunteer their boat, so the best approach is to see if it's already happened by accident. Are there any detailed accounts of the recent sinking in Alaska that would answer the question? Joe.
A
Anonymous
Guest
Sea Wolf":3m3m001l said:Sometimes it's probably better if the boat sinks somewhere safe from further damage until it can be later raised and rescued.
Great thinkin :idea I'd say up here in AK... most the time it would be better if the thing sank!! too many rocks along just about any shore up here :!: Don't know about any news of the swamped 25. I ain't had the time to pay attention to nuttin lately but work around here :cry :disgust
Hi, All,
Some of the earlier discussions on this subject can be found below (Sorry, still haven't figured out how to do a simple link here).
LINK
The USCG requires that boats under 20 feet have built-in foam flotation. 20 feet and above, and you're on your own.
We know that the 25's have foam, but I still haven't seen anything about the 22's.
The question for the 22 footers has never really been answered, at least as far as anything definitive that I can find. See Mark Toland's answer to me (as shown in the above link). I treat my boat as sinkable, and plan accordingly. It supposedly will float in a bow-up attitude, but I just don't know how to do the math and figure out all the stuff that floats versus the stuff that sinks.
Gasoline is something like 75% the weight of water, so it floats. If your tanks are full, they will add to the flotation of the stern. If they're empty, you'll float even better.
To me, the bottom line is that even if the boat floats, it's not going to be high enough in the water to get you out of the water. So you should still plan for all the contingencies, like wearing PFDs, carrying EPIRBs, the means to call for assistance, and such.
Ken
Link edited by Da Nag
Some of the earlier discussions on this subject can be found below (Sorry, still haven't figured out how to do a simple link here).
LINK
The USCG requires that boats under 20 feet have built-in foam flotation. 20 feet and above, and you're on your own.
We know that the 25's have foam, but I still haven't seen anything about the 22's.
The question for the 22 footers has never really been answered, at least as far as anything definitive that I can find. See Mark Toland's answer to me (as shown in the above link). I treat my boat as sinkable, and plan accordingly. It supposedly will float in a bow-up attitude, but I just don't know how to do the math and figure out all the stuff that floats versus the stuff that sinks.
Gasoline is something like 75% the weight of water, so it floats. If your tanks are full, they will add to the flotation of the stern. If they're empty, you'll float even better.
To me, the bottom line is that even if the boat floats, it's not going to be high enough in the water to get you out of the water. So you should still plan for all the contingencies, like wearing PFDs, carrying EPIRBs, the means to call for assistance, and such.
Ken
Link edited by Da Nag
Perhaps the question should be posed a little differently.
Is the concern the life-supporting attitude of the boat once it sinks (or at least fills with all the water it will allow), or one of recovery once it goes to the bottom?
I'm gonna guess that it is the former. And my guess is that the boat is going to be pretty much swamped, with very little of the superstructure above water. So it will be a very important "island" for any not wearing their PFDs at the time of the mishap.
So if the question is "will my boat save me if it gets holed or swamped", the answer is probably yes, according to at least a few responses from the factory. It'll probably give you enough to hang on to in such an event.
Ken
Is the concern the life-supporting attitude of the boat once it sinks (or at least fills with all the water it will allow), or one of recovery once it goes to the bottom?
I'm gonna guess that it is the former. And my guess is that the boat is going to be pretty much swamped, with very little of the superstructure above water. So it will be a very important "island" for any not wearing their PFDs at the time of the mishap.
So if the question is "will my boat save me if it gets holed or swamped", the answer is probably yes, according to at least a few responses from the factory. It'll probably give you enough to hang on to in such an event.
Ken
Considering all of this, it might be a very good procedure for those knowingly going into seriously dangerous situations to carry an inflatable on the roof lashed down tightly so that the resultant total buoyancy package would float upright instead of inverted.
I'd then also attach a ditch bag to this inflatable with a serrated rope cutting knife in an outer zippered pocket to free the dinghy if desired.
Ditch bag ditties: (in no particular order)
waterproof VHF radio
spare life jacket (s)
immersion suits or equivalent (depends on water temperatures anticipated)
EPIRB
First Aid Kit
water and food
signal flares, rockets, flare pistol, mirror, dye, waterproof flashlight, etc.
spare ropes, duct tape, knife, multi-tool, etc.
bottle of Harvey's Bristol Cream (or equivalent) for last sacrament (just kidding)
I'd then also attach a ditch bag to this inflatable with a serrated rope cutting knife in an outer zippered pocket to free the dinghy if desired.
Ditch bag ditties: (in no particular order)
waterproof VHF radio
spare life jacket (s)
immersion suits or equivalent (depends on water temperatures anticipated)
EPIRB
First Aid Kit
water and food
signal flares, rockets, flare pistol, mirror, dye, waterproof flashlight, etc.
spare ropes, duct tape, knife, multi-tool, etc.
bottle of Harvey's Bristol Cream (or equivalent) for last sacrament (just kidding)
Salmon Slayer
New member
Flotation is of limited value up here for life saving unless you can get out of the water (water temp is cold enough to kill you in about 10 min) so I think geographical considerations might be an important part of this discussion. I am seriously looking at a similar project to REDFOX except use it for storage.
I always assume the boat will sink, take a cautious approach to weather, and plan on beaching if possible (we are usually close to some island or shoreline).
I am more afraid of falling in the water from the boat and not being able to get back aboard because of the high free board. I fell off my dads fishing boat once and after 5 minutes in the water I could hardy help to get back into the boat I was so cold. I am looking at coming up with a portable boarding ladder for the next season for this purpose.
I always assume the boat will sink, take a cautious approach to weather, and plan on beaching if possible (we are usually close to some island or shoreline).
I am more afraid of falling in the water from the boat and not being able to get back aboard because of the high free board. I fell off my dads fishing boat once and after 5 minutes in the water I could hardy help to get back into the boat I was so cold. I am looking at coming up with a portable boarding ladder for the next season for this purpose.
starcrafttom
Active member
Talking about falling in the water. We all have auto inflate life vest on the susan E. If i go over the side there is a good chance that I was knocked out first. Can't really see how i would get tossed other wise. With the self inflating vest as soon as you hit the water they inflate. Its almost as fast a car air bag. So right there you have increased your chances for survival. The thing I find most useful about the self inflating vest is that being they are really thin and light before they inflate I am more likely to wear one then a large thick vest. In fact I have loaded the boat and drove to wendys for a burger, got out of the car and stopped half way to the door to take off my life vest and but it in the car. I have not made it in to wendys yet but my friend cliff went to work after a morning of fishing with his on. Good thing he works for him self.
Tom... Tell me now... with all the time you have spent on and around boats you have never fallen in?? I thought you had more fun than that... :cry
Well.... I have hit the water without intent twice. Once AT THE DOCK... most dangerous I thought, cold, dark and alone..... and once on a fall evening star gazing cruise with old boat just in forward..... air temp around 55.....water temp around 65... and wow was that air cold once back on board.... and sneaking up that long trail rope with a fender on the end of it was not as easy as it looks in the movies either.... but was good "training." Yep, your self inflating individual air bags are my next "buy for the boat items" that I will more than likely take advantage of at the SBS if they have some good deals.
Well.... I have hit the water without intent twice. Once AT THE DOCK... most dangerous I thought, cold, dark and alone..... and once on a fall evening star gazing cruise with old boat just in forward..... air temp around 55.....water temp around 65... and wow was that air cold once back on board.... and sneaking up that long trail rope with a fender on the end of it was not as easy as it looks in the movies either.... but was good "training." Yep, your self inflating individual air bags are my next "buy for the boat items" that I will more than likely take advantage of at the SBS if they have some good deals.
If I were alone or even with one other person in a C-Dory in any really cold ocean situation where survival time was measured in minuters and the weather was rough, Id be wearing a Mustang work suit with all the built in flotation and survival gear necessary to last for a while. This is a working suit and not the total immersion suit you put on board when you KNOW you're going DOWN. Alaska Commercial fisherman wear a lot of them.
I've had one on before courtesy of the Coast Guard, and they're worth every penny of the $450 or so! I'll bet you'd pay several times that for one once you're overboard in freezing water. The Coasties wear an additional vest over the Mustang that contains a strobe / flashlight, a whistle, a pack of hand held rockets, a sharp but dull pointed knife, a reflecting mirror, dye packets, and several other goodies.
Other possible accomplaces for your swim might include a hand-held VHF, satellite cell phone, an EPIRB, a bottle of your favorite gut warmer, a rabbit's foot, etc.
Fun is fun, and survival is survival, but a little prepardness goes a long way down the road either way. Joe.
P.S.: I have an emergency boarding ladder mounted on the port stern of my CD just for the purpose of getting back in after an unscheduled MOB drill. Never had to use it in an emergency so far. Nice knowing it's there, but doesn't do much good if the boat's in gear! Like the trailing rope idea, but fishing would make it complicated. Easier to rig a harness/lifeline like we used on big sailboats.
I've had one on before courtesy of the Coast Guard, and they're worth every penny of the $450 or so! I'll bet you'd pay several times that for one once you're overboard in freezing water. The Coasties wear an additional vest over the Mustang that contains a strobe / flashlight, a whistle, a pack of hand held rockets, a sharp but dull pointed knife, a reflecting mirror, dye packets, and several other goodies.
Other possible accomplaces for your swim might include a hand-held VHF, satellite cell phone, an EPIRB, a bottle of your favorite gut warmer, a rabbit's foot, etc.
Fun is fun, and survival is survival, but a little prepardness goes a long way down the road either way. Joe.
P.S.: I have an emergency boarding ladder mounted on the port stern of my CD just for the purpose of getting back in after an unscheduled MOB drill. Never had to use it in an emergency so far. Nice knowing it's there, but doesn't do much good if the boat's in gear! Like the trailing rope idea, but fishing would make it complicated. Easier to rig a harness/lifeline like we used on big sailboats.
A
Anonymous
Guest
Salmon Slayer":4jdqahbl said:I am seriously looking at a similar project to REDFOX except use it for storage.
So did ya yet? Now I have more free storage to finally post the making of that area in my boat... watch for it :!: ]
Salmon Slayer
New member
RedFox: I have only gotten as far as a lookiloo and a cringe about cutting into the area, your project notes and pics if you have them would be extremely welcome!!